A power converter including a transformer, a resonant circuit including the transformer and a resonant capacitor having a characteristic resonant frequency and period, and output circuitry connected to the transformer for delivering a rectified output voltage to a load. Primary switches drive the resonant circuit, a switch controller operates the primary switches in a series of converter operating cycles which include power transfer intervals of adjustable duration during which a resonant current at the characteristic resonant frequency flows through a winding of the transformer. The operating cycles may also include energy recycling intervals of variable duration for charging and discharging capacitances within the converter. A gate driver includes a transformer, a plurality of switches, a current monitor, and a controller that operates the switches in a series of driver operating cycles having adjustable ON periods and adjustable transition periods during which capacitances are resonantly charged and discharged.
Legal claims defining the scope of protection, as filed with the USPTO.
3. The apparatus of claim 2, wherein the switch controller is configured to adjust the duration of each energy recycling interval, TERI, to vary from a maximum duration, TERI-MAX, at times when the duration of the power transfer interval is set to the predetermined minimum duration, TPTI-MIN, and to a minimum duration, TERI-MIN, at times when the duration of the power transfer interval is set to the predetermined maximum duration, TPT-MAX.
4. The apparatus of claim 2, wherein the first predetermined threshold, IL1, is greater than or equal to 33 percent of the maximum load current, IL-MAX.
5. The apparatus of claim 2, wherein the first predetermined threshold, IL1, is greater than or equal to 50 percent of the maximum load current, IL-MAX.
6. The apparatus of claim 2, wherein the first predetermined threshold, IL1, is greater than or equal to 65 percent of the maximum load current, IL-MAX.
7. The apparatus of claim 2, wherein the second predetermined threshold, IL2, is approximately equal to the minimum load current, IL-MIN.
8. The apparatus of claim 7, wherein the minimum load current, IL-MIN, is zero.
9. The apparatus of claim 2, wherein the predetermined minimum duration, TPTI-MIN, is greater than or equal to 25 percent of the characteristic resonant period.
10. The apparatus of claim 2, wherein the predetermined minimum duration, TPTI-MIN, is in a range between 25 to 35 percent of the characteristic resonant period.
11. The apparatus of claim 1, wherein the switch controller is configured to turn the two or more primary switches ON at times when a voltage across the respective primary switch, VSW, of the two or more primary switches is approximately zero.
12. The apparatus of claim 1, wherein the switch controller is configured to turn the two or more primary switches ON at times when a voltage across the respective primary switch, VSW, of the two or more primary switches is less than 25 percent of a maximum voltage across the respective primary switch, VSW-MAX, of the two or more primary switches in the OFF state during normal operation.
13. The apparatus of claim 1, further comprising a non-isolated power train.
14. The apparatus of claim 1, wherein the input circuitry and at least a portion of the output circuitry are connected in series across the source such that an absolute value of an input voltage VIN applied to the input circuitry is approximately equal to an absolute value of the source voltage VS minus a number N times an absolute value of the output voltage VOUT, where N is at least 1.
16. The apparatus of claim 1, wherein the switch controller comprises a digital controller.
17. The apparatus of claim 16, wherein timing parameters, including the durations of the two power transfer intervals, are digitally set and adaptively reset using at least one look-up table as a function of the load.
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October 19, 2023
October 29, 2024
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